Process for preparing cumene which is used in the preparation of phenol

Abstract

Disclosed is a method for the preparation of cumene by reacting isopropanol or a mixture of isopropanol and propene with benzene in the presence of a β-zeolite catalyst having a SiO 2 /Al 2 O 3 molar ratio greater than 10:1 that can be integrated in a process for preparing phenol, which comprises preparing cumene as described above, oxidizing cumene to cumene hydroperoxide, acid-catalyzed cleavage of cumene hydroperoxide to give phenol and acetone, and hydrogenating acetone to form isopropanol.

1. A method for the preparation of cumene comprising reacting isopropanol or a mixture of isopropanol and propene with benzene in presence of a β-zeolite catalyst having a SiO 2 /Al 2 O 3  molar ratio greater than 10:1, wherein the acidity of the catalyst is modified by surface addition of water, and wherein the isopropanol used is obtained by hydrogenation of acetone in at least two process stages. 
     
     
       2. The method of  claim 1 , wherein the catalyst used is a β-zeolite having an SiO 2 :Al 2 O 3  ratio of from 20:1 to 200:1. 
     
     
       3. The method of  claim 1 , wherein the reacting occurs in a reactor that receives a feed stream, and wherein the water content of the total feed stream to the reactor does not exceed 5 wt.-% based on the weight of the total feed stream. 
     
     
       4. The method of  claim 3 , wherein the water content ranges from 0.1 to 5 wt.-%. 
     
     
       5. The method of  claim 1 , wherein the reacting occurs in a reactor that receives a feed stream, and wherein the molar ratio of benzene to isopropanol in the feed stream to the reactor is greater than 1:1. 
     
     
       6. The method of  claim 5 , wherein the molar ratio of benzene to isopropanol in the feed stream to the reactor for the reaction of benzene with isopropanol is from 3:1 to 10:1. 
     
     
       7. The method of  claim 1 , wherein the reaction is carried out at a temperature of from 100 to 300° C. 
     
     
       8. The method of  claim 1 , wherein the reaction is carried out at a pressure of from 10 to 100 bar abs. 
     
     
       9. The method of  claim 1 , wherein the reaction is carried out in a stirred tank reactor, a trickle-bed reactor or a fixed-bed reactor. 
     
     
       10. The method of any  claim 1 , wherein the reacting occurs in a reactor that receives a feed stream, and wherein the reaction mixture is, after leaving the reactor, separated into an aqueous phase and an organic phase by liquid/liquid phase separation. 
     
     
       11. The method of  claim 10 , wherein part of the organic phase of the reaction mixture is returned to the reactor. 
     
     
       12. The method of  claim 11 , wherein the ratio of the recycled organic phase of the reaction mixture to starting materials is from 2:1 to 100:1. 
     
     
       13. The method of  claim 1 , wherein the reaction mixture has an n-propylbenzene concentration of less than 300 wppm. 
     
     
       14. A method for preparing phenol from benzene, comprising:
 preparing cumene, comprising reacting isopropanol or a mixture of isopropanol and propene with benzene in presence of a β-zeolite catalyst having a SiO 2 /Al 2 O 3  molar ratio greater than 10:1, wherein the acidity of the catalyst is modified by surface addition of water,  
 oxidizing cumene to cumene hydroperoxide,  
 performing an acid-catalyzed cleavage of cumene hydroperoxide to give phenol and acetone; and  
 hydrogenating acetone to form isopropanol, wherein the isopropanol used is obtained by hydrogenation of acetone in at least two process stages.  
 
     
     
       15. The method of  claim 14 , wherein the acetone used is crude acetone. 
     
     
       16. A method for the hydrogenation of acetone to isopropanol, wherein said hydrogenation of acetone to isopropanol comprises at least two process stages, and wherein the acetone used is crude acetone. 
     
     
       17. The method of  claim 14 , wherein the hydrogenation is carried out as a liquid-phase hydrogenation at a temperature of from 60 to 140° C. and a pressure of from 20 to 50 bar. 
     
     
       18. The method of  claim 15 , wherein the crude acetone contains up to 15% by weight of impurities. 
     
     
       19. The method of  claim 18 , wherein the crude acetone contains from 2.5 to 13% by weight of impurities. 
     
     
       20. The method of  claim 18 , wherein the crude acetone contains up to 5% by weight of water. 
     
     
       21. The method of  claim 18 , wherein the crude acetone contains up to 7.5% by weight of cumene. 
     
     
       22. The method of  claim 18 , wherein the crude acetone contains up to 3000 wppm of acetaldehyde. 
     
     
       23. The method of  claim 14 , wherein the acetone conversion in the hydrogenation is at least 99%. 
     
     
       24. The method of  claim 14 , wherein a catalyst comprising Ni, Cu, Ru, Cr or a mixture thereof on a neutral support is used for the hydrogenation. 
     
     
       25. The method of  claim 24 , wherein a nickel-containing catalyst on an α-Al 2 O 3  support is used. 
     
     
       26. The method of  claim 4 , wherein the water content ranges from 0.5 to 4.5 wt.-%. 
     
     
       27. The method of  claim 1 , wherein the reaction mixture has an n-propylbenxene concentration of less than 150 wppm. 
     
     
       28. The method of  claim 20 , wherein the crude acetone contains up to 7.5% weight of cumene. 
     
     
       29. The method of  claim 19 , wherein the crude acetone contains up to 3000 wppm of acetaldehyde. 
     
     
       30. The method of  claim 18 , wherein the acetone conversion in the hydrogenation is at least 99%. 
     
     
       31. The method in  claim 30 , wherein the acetone conversion in the hydrogenation is at least 99%. 
     
     
       32. The method of  claim 18 , wherein a catalyst comprising Ni, Cu, Ru, Cr or a mixture thereof on a neutral support is used for the hydrogenation. 
     
     
       33. The method of  claim 30 , wherein a catalyst comprising Ni, Cu, Ru, Cr or a mixture thereof on a neutral support is used for the hydrogenation. 
     
     
       34. The method of  claim 33 , wherein a nickel-containing catalyst on an α-Al 2 O 3  support is used. 
     
     
       35. The method of  claim 16 , wherein the hydrogenation is carried out as a liquid-phase hydrogenation at a temperature of from 60 to 140° C. and a pressure of from 20 to 50 bar. 
     
     
       36. The method of  claim 16 , wherein the crude acetone contains up to 15% by weight of impurities. 
     
     
       37. The method of  claim 16 , wherein the acetone conversion in the hydrogenation is at least 99%.